Hi there, Tom of Finland Foundation.
The duplicate file might have been created when you upgraded the file. Each version of QuickBooks has its own folder in the default directory after installing it. It's also possible that it was created when restoring a backup copy. QuickBooks will prompt you to save a working file, and it might have been saved in the folder that you've mentioned.
As long as you continue yo use the one in your network file server, you can remove the duplicate file to avoid confusion. Just make sure you're deleting the one in the default directory to avoid access issue when logging in to the company file.
We also advise to always save a backup copy to make sure that everything is covered. Here's an article for more details: Back Up Your QuickBooks Desktop company file.
Please don't hesitate to reach out to us again if you need anything else.
